Wetting of water repellent soil by low HLB EO/PO block copolymers and enhancing solubility of same

ABSTRACT

Water repellent soil is treated with low concentrations of EO/PO block copolymer having an HLB value of less than or equal to 2; an average molecular weight of greater than 3,000; and a percent hydrophile of 10 in order to rapidly increase the wetting rate of the water repellent soil.

The present patent application claims the benefits accorded under 35U.S.C. 119(e) of prior provisional application 60/328,027 filed Oct. 9,2001 and is a Continuation In Part of the prior patent application U.S.Ser. No. 10/265,950 filed Oct. 7, 2002.

FIELD OF THE INVENTION

The present invention generally relates to the use of certain blockcopolymer surfactants to enhance the infiltration of water and/oraqueous compositions through water repellent soil. More particularly,the present invention relates to the use of ethylene oxide-propyleneoxide block copolymers to rapidly improve the hydrophilicity of suchsoil.

BACKGROUND OF THE INVENTION

Agriculturalists have to work with all types of plant growth media suchas sand, natural earth, horticultural soils, and various soil-mimicking,soil-less plant culture substrates; however, the bane of essentially allagriculturalists is water repellent soil. Water repellent soil retardswater infiltration into the soil matrix and often renders entire areasof the upper layers of the soil substrate essentially impervious towater penetration. Under rainfall or irrigation conditions, direenvironmental consequences can result from the water repellency of thetopsoil, such as surface runoff of water and aqueous compositionscontaining pesticides, this term inclusive of fertilizers, into pristineareas and/or potable reservoirs. Furthermore, and less obvious, are theserious consequences that result from aqueous pesticide flow through“fingers” that usually attend water repellent soil which can providerapid transport of pesticide compositions to the local ground watertable and thus increase the risk of ground water contamination.

Water repellency of a soil is not only a function of the initial watercontent of the soil, but is also a function of soil particle size (sandsare more prone to water repellency than clays), as well as, type oforganic matter incorporated in it. This organic matter induces waterrepellency in the soils in many ways, such as by providing hydrophobicorganic substances leached from the plant litter; organic substancesthat have been irreversibly dried; and microbial by-products.

Before water will evenly infiltrate into or percolate through a soilmatrix, there must be a continuous film of water on the soil particles.In other words, the soil must first be wetted before water will flow. Inaddition, getting the soil evenly wetted is of paramount importance tothe healthy growth of plants or seeds which are to be grown in the soil.Thus, agriculturalists will often apply various wetting agent surfactantcompositions directly to the soil or admix same with aqueous pesticideformulations to reduce the surface tension of the composition beforeapplying the pesticide to the plant growth media as taught, for example,in U.S. Pat. Nos. 2,867,944; 5,595,957; 5,385,750; WO 96134078; and WO98/39273.

“Although an increasing number of researchers are aware of theoccurrence and consequences of water repellency in a wide range ofsoils, it is still a neglected field in soil science.” (Dekker et al.,International Turfgrass Society Research Journal, Volume 9, 2001, pages498-505)

It has been recognized for years that in water repellent soilsignificant spatial variability can occur both in soil water content anddegree of water repellency. Agriculturalists have attacked the soilwater repellency problem through the use of wetting agent surfactantcompositions. The degree of efficacy among chemistries and formulationshave varied significantly. Often, the amount of surfactant required toameliorate water repellency and/or to enhance infiltration, eitherperform variably or in an attempt to improve performance, higher ratesof wetting agents are applied, such elevated rates often becominginjurious to plants.

Thus, there is a continuing search for wetting agent compositions withincreased wetting rate that are able to quickly penetrate and infiltratethe water repellent soil. The use of wetting agent compositions withincreased wetting rates, in turn, will result in a more effectivewetting of the root zone during rain events and/or irrigationapplications, thereby, inducing better plant growth and decreasedrun-off.

SUMMARY OF THE INVENTION

The instant invention provides a process for rapidly increasing thehydrophilicity and infiltration of water into water repellent soilmatrices. The process consists of applying to the water repellent soilan effective amount of a wetting agent composition comprising certainspecific ethylene oxide-propylene oxide (EO/PO) block copolymers with orwithout solubility enhancing additives. These compositions unexpectedlyexhibit significantly enhanced infiltration (wetting) rates in waterrepellent soil.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention specifically relates to the discovery that wettingagent compositions comprising ethylene oxide-propylene oxide (EO/PO)block copolymers having an HLB value of less than or equal to 2; anaverage molecular weight of greater than 3,000; and a percent hydrophileof less than or equal to 10 significantly and unexpectedly enhance waterand aqueous composition transport or infiltration through the solidmatrices of water repellent soil. Additionally, it has been found thatthese compositions are highly efficacious over a wide range ofconcentrations which is of critical importance in achieving maximumagronomic and/or hydrological benefit when the compositions are to beused in irrigation scenarios, e.g., both for the reduction in run-offand in the delivery of water soluble fertilizers.

The HLB (Hydrophilic-Lipophilic Balance) is a system designed to assignmost surfactant materials a number which describes its hydrophilic orlipophilic tendencies. Surfactants that are more hydrophilic tend tohave a higher HLB value. Conversely, lower HLB numbers denote a morehydrophobic surfactant composition.

The commonly accepted method of classifying the water repellency ofsoils is the Water Drop Penetration Time (WDPT) test (ibid.). In thistest, drops of distilled water from a standard medicine dropper areplaced on the smoothed solid surface of a soil sample, and the time thatelapses before the drops are completely absorbed is determined. All WDPTtests are conducted under controlled conditions usually at a constanttemperature of about 20° C. and a relative air humidity of about 50%.These tests are normally replicated three times.

Although soil water repellency is a relative property, varying inintensity, it is generally recognized in the art that a soil is to beconsidered water repellent if the WPDT exceeds five seconds. This allowssoils to be qualitatively classified and referred to as being eitherwettable or water repellent. The instant invention is specificallydirected to rapidly increasing the hydrophilicity of water repellentsoil.

The ethylene oxide-propylene oxide (EO/PO) block copolymers of theinstant invention include the straight block polymeric glycols obtained,for example, by the addition of ethylene oxide (EO) on a condensationproduct of propylene oxide (PO) with propylene glycol. Reverse blockcopolymers, which are also acceptable for use in the instant invention,are prepared by adding ethylene oxide to ethylene glycol to provide ahydrophile of designated molecular weight. Polypropylene oxide is thenadded to obtain hydrophobic blocks on the outside of the molecule.Reversing the hydrophobic and hydrophilic blocks creates surfactantssimilar to the regular EO/PO/EO block copolymers, but with someimportant differences. While the EO/PO/EO straight block copolymers tendto be better emulsifiers and dispersants and cover a broader range ofmolecular weights, the reverse block copolymers have lower foaming,greater defoaming, and reduced gelling tendencies. Additionally, reverseblock copolymers are terminated by secondary hydroxyl groups, which havelower reactivity and acidity than the primary hydroxyl groups whichterminate the EO/PO/EO straight block copolymers.

The tetra-functional block copolymers and their reverse counterparts,are derived from the sequential addition of propylene oxide and ethyleneoxide to ethylene diamine.

Irrespective of the specific structural type, or configuration, asstated above, the EO/PO block copolymers which are useful in the instantinvention are those having an HLB value of less than or equal to 2; anaverage molecular weight of greater than 3,000; and a percent hydrophileof less than or equal to 10.

The concentration of the wetting agent compositions of this invention inthe aqueous formulations to be applied to the water repellent soil isnot critical. Wetting agent composition levels of up to 200,000 ppm arecontemplated in this invention for those concentrations arenon-injurious to most plant. Thus, the concentration of the wettingagent in the compositions will range from about 200,000 to about 2 ppm;preferably from about 120,000 to about 5 ppm. One of the surprisingfeatures of the use of these wetting agent compositions is theoutstanding effectiveness at very low concentrations: a highly desirableenvironmental property. In any event, appropriate concentration levelsare easily determined by those skilled in the art.

By the term “effective amount” in the water repellent soil is meant thepresence in the soil of an amount of the EO/PO block copolymer (A)having an HLB value of less than or equal to 2; an average molecularweight of greater than 3,000; and a percent hydrophile of less than orequal to 10 such that were it to be the only wetting rate increasingactive present in the soil, it would provide a measurable increase inthe wetting rate of the soil. Preferably, the total amount of the EO/POblock copolymer (A) having an HLB value of less than or equal to 2; anaverage molecular weight of greater than 3,000; and a percent hydrophileof less than or equal to 10 active composition in the initially waterrepellent soil, including any additional wetting rate increasing activesif present, is in the range of from 0.25 kg/hectare to 110 kg/hectare.When referring to solid granular or powder wetting agent compositions,the “effective amount” in the water repellent soil is an amount that, ifan aqueous composition were to be prepared consisting only of water andsaid copolymer (A) and intimately applied to said soil such that thecopolymer (A) concentration in said soil is the same as when the solidwetting agent composition is applied, said copolymer (A) amount wouldprovide a measurable increase in the wetting rate of the soil.

When the composition consists of a) an ethylene oxide—propylene oxideblock copolymer (A) wherein the copolymer has an HLB value of less thanor equal to 2; an average molecular weight of greater than 3,000; and apercent hydrophile of less than or equal to 10; b) an ethylene-propyleneoxide block copolymer (B) having an HLB value greater than 2 and anaverage molecular weight of from 2,000 to 8,000; and water, there isfrom 99 to I parts by weight copolymer (A); and from 1 to 99 parts byweight copolymer (B) wherein the total parts by weight is 100 and isbased on the total weight of copolymers (A) and (B). When thecomposition consists of a) an ethylene oxide—propylene oxide blockcopolymer (A) wherein the copolymer has an HLB value of less than orequal to 2; an average molecular weight of greater than 3,000; and apercent hydrophile of less than or equal to 10; b) analkylpolyglycoside; and c) water, the composition consists of a) from 99to 1 parts by weight copolymer (A); and b) from 1 to 99 parts by weightalkylpolyglycoside wherein the total parts by weight is 100 and is basedon the total weight of copolymer (A) and the alkylpolyglycoside. Whenthe composition consists of a) an ethylene oxide—propylene oxide blockcopolymer (A) wherein the copolymer has an HLB value of less than orequal to 2; an average molecular weight of greater than 3,000; and apercent hydrophile of less than or equal to 10; b) an ethylene-propyleneoxide block copolymer (B) having an HLB value greater than 2 and anaverage molecular weight of from 2,000 to 8,000; c) analkylpolyglycoside; and d) water; the composition consists of a) from 98to 1 parts by weight copolymer (A); b) from 1 to 98 parts by weightcopolymer (B); and c) from 1 to 98 parts by weight alkylpolyglycosidewherein the total parts by weight is 100 and is based on the totalweight of copolymer (A); copolymer (B); and the alkylpolyglycoside.

A simple laboratory “straw” test developed by Aquatrols Corporation ofAmerica can be used to record the initial effectiveness of a wettingagent composition on water repellent soil. (International TurfgrassSociety Research Journal 7. Intertec Pubishing Corp. 1993 Chapter 67,pages 485-488) The straw test consists of taking clear plastic drinkingstraws (19 cm. in length and 0.5 cm. in diameter) and folding them inthe center to give a sharp “V” shape, i.e., no flat crimps. Adhesivetape is used to hold the two arms of the straw in this “V” position. Onearm of the straw is filled with hydrophobic soil while tapping the strawgently on a solid surface to ensure even settling of the soil in thestraw. The resulting soil column is plugged with cotton and the strawsarranged on a flat support. Test solutions at selected concentrationsare introduced individually into each of the empty arms of the strawswith a pasteur capillary pipet. The arm containing the hydrophobic soilcolumn is laid horizontally on the support surface; the adhesive taperemoved; and the arm containing the test solution lowered toward thesupport surface until the arm is at a 25° angle to the surface.

A wedge or support is fixed to the surface to ensure that the strawangle is maintained throughout the test. A stopwatch is started as soonas a test solution comes in contact with the hydrophobic soil and thetime to wet a 6 cm. length of the soil column is recorded. Distilledwater is usually used as a standard. This straw test is sensitive toconcentrations as low as 10 ppm.

Other than in the operating examples, or where otherwise indicated, allnumbers expressing quantities of ingredients or reaction conditions usedherein are to be understood as modified in all instances by the term“about”.

The following examples will further illustrate, but not limit, theinvention with all percentages and ratios being by weight unlessotherwise indicated.

EXAMPLE 1

The water repellent soil which is used in the following examples is madeby coating a hydrophilic sand with octadecyl trichloro silane (OTS) asdescribed by Bauters, et al., 1998 Soil Sci. Soc. Am. J. 62: 1185-1190.

Using the aforedescribed straw test, the infiltration rate in seconds ofdistilled water through a six centimeter column of this water repellentsoil is determined through three replications. The results are set forthin Table I. TABLE I Treatment Replication 1 Replication 2 Replication 3Average Distilled 604,800 s 691,200 s 604,800 s 633,600 s Water

These numbers indicate the base-line hydrophobicity of this mineral soiland serve as the control in the quantification of the performance ofwetting agent compositions tested.

Water droplet penetration time (WDPT) tests were also performed on thismineral soil in the following manner: The soil is evenly loaded into adeep container and the surface smoothed to realize a flat,unconsolidated substrate surface.

A 30 microliter drop of distilled water is placed on the sample surface.A stopwatch is started when the water drop contacts the soil surface andterminated when the drop is totally absorbed by the soil. The time isrecorded in seconds.

The WDPF values obtained with the instant mineral soil prepared aboveall exceed six hours (21,600 sec) and thus this soil is extremelyhydrophobic, i.e., clearly water repellent.

EXAMPLE II

Aqueous compositions of numerous EO/PO block copolymers inconcentrations as indicated below are examined using the aforedescribedstraw test in order to ascertain their ability to affect theinfiltration wetting rate of the water repellent soil of Example 1.Tetronic is a trademark of BASF for its EO/PO ethylene diamine basedblock copolymers. Straight “L” block copolymers and reverse “R” blockcopolymers are produced by various manufacturers such as Rhodia, BASF,and Uniqema.

The results of the tests are set forth in Tables IIA and IIB below.TABLE IIA Total Concentration in Water (ppm) 8000 6000 4000 2000 WettingAgent Composition Infiltration Time (Sec.) Straight EO/PO BlockCopolymers L61 35.25 58 62.25 98.75 L62 59 69.75 105.5 120 L64 55.33110.33 259 376.33 L92 35 41.5 44.75 154.67 L101 43.2 32.25 41 64 ReverseEO/PO Block Copolymers 31R1 80.5 1770.25 17R2 2183 100000 25R2 161.53640.67 10R5 100000 100000 17R4 100000 100000 Diamine-Based EO/PO BlockCopolymers TETRONIC 304 100000 100000 TETRONIC 701 3227 3568.75 TETRONIC901 166.25 14362.25 TETRONIC 1301 42.5 86.25 Diamine-Based EO/PO ReverseBlock Copolymers TETRONIC 90R4 82738.75 100000 TETRONIC 150R1 43.5 50.50

TABLE II B Average Molecular % Hydrophile HLB Value Weight StraightBlocks (EO-PO-EO L31 10% 5 1,100 L61 10% 3 2,000 L62 20% 7 2,500 L64 40%15 2,900 L92 20% 6 3,650 L101 10% 1 3,800 Reverse Blocks (PO-EO-PO) 25R220% 4 3,100 31R1 10% 1 3,250 17R2 20% 6 2,150 10R5 50% 15 1,950 17R4 40%12 2,650 Tetra Blocks (EO-PO added to ethylenediamine) TETRONIC 304 40%16 1,650 TETRONIC 701 10% 3 3,600 TETRONIC 901 10% 3 4,700 TETRONIC 130110% 2 6,800 TETRONIC 90R4 40% 7 7,240 TETRONIC 150R1 10% 1 8,000

The above straw test results clearly show the outstanding and unexpectedresults realized in the increase in the infiltration rate when the EO/POblock copolymers of this invention at the concentrations tested areapplied to water repellent soil.

It is observed from the above results that the soil wetting speedincreases (wetting time decreases) with increasing hydrophobe molecularweight and decreasing HLB Value within each particular EO/PO blockcopolymer structural type, i.e., the straight EO/PO block copolymers;the reverse EO/PO block copolymers; the diamine-based EO/PO blockcopolymers; and the diamine-based EO/PO reverse block copolymers.

Stated another way, generally EO/PO surfactants with a lower HLB valueand a higher average molecular weight show the shortest infiltrationtimes through a column of hydrophobic soil. Furthermore, the HLB valueis the dominant property with respect to the efficacy of wetting of thewater repellent soil. The molecular weight property is a secondarycharacteristic in that if two surfactants were to have the same HUBvalue, the one with the higher molecular weight usually will realizeenhanced wetting properties as compared to the lower molecular weightsurfactant composition. This trend holds true for all four surfactantstructural types.

Unfortunately, water solubility tends to decrease with increasinghydrophobe molecular weight and decreasing HLB value within eachparticular structural type. This behavior would possibly limit the useof some of these particular compounds to treat water-repellent soilsespecially if it were desired to formulate some in high concentrations,for if a stable aqueous solution cannot be produced, the material cannotbe effectively and/or efficiently applied to soils.

Serendipitously, it has been discovered that by judiciously blendingEO/PO block copolymers having high HLB values with the highly desirable,low HLB value block copolymers of the instant invention which, at thedesired concentration, may possess poor water solubility if used alone,the overall solubility of the blend can be significantly enhanced whileessentially retaining the greatly reduced infiltration time throughwater repellent soil.

EXAMPLE III

This example illustrates the use of a high HLB value EO/PO blockcopolymer to increase the solubility of an EO/PO block copolymer of theinstant invention, i.e., one having an HLB value of less than or equalto 2; an average molecular weight of greater than 3,000; and a percenthydrophile of less than or equal to 10.

Tetronic 150R1 previously shown to exhibit strong efficacy in thewetting of water repellent soil shows poor water solubility which couldlimit its potential commercially. Antarox L64, a straight EO/PO blockcopolymer sold by Rhodia Inc., which has an HLB value of 15; an averagemolecular weight of 2,900; and a percent hydrophile of 40% is blended ina 1:1 weight ratio with the Tetronic 150R1. The wetting characteristicsusing the straw test of the individual components and the blend are setforth in Table III below. It should be noted that the data generated ona straight dilution of Tetronic 150R1 were based on a partially solubletest solution. TABLE III COMPONENT/FORMULATION Infiltration Time at 2000ppm (s) Tetronic 150R1 (BASF) 50.5 ANTAROX L64 (Rhodia) 376.33 1:1 150R1to L64 71

The results show that this surfactant blend of the low HLB value (1)Tetronic 150R1 and the high HLB value (15) Antarox L64 exhibits wettingtimes (71 seconds) very similar to the “target” compound Tetronic 150R1alone (50.5 seconds). Furthermore, this blend at a concentration of2,000 ppm is a uniform and room temperature stable, aqueous solution.

Also, it has been discovered that by adding the alkyl polyglycosides tothe EO/PO block copolymers to prepare the blends of the instantinvention, the cloud point of the blend can be raised above that of theblock copolymer alone and, in some cases, solubility can even be inducedto a previously essentially insoluble compound.

EXAMPLE IV

This example illustrates the surprising effect that alkyl polyglycosideshave upon the cloud point and thus the solubility of the blockcopolymers, i.e., the four structural types, and thus the blends of thisinvention. EO/PO block copolymers Pluronic L121, Pluronic 31R1, Tetronic1301, and Tetronic 150R1 are blended as indicated in the followingweight percent table with AtPlus 452, the trademark for an alkylpolyglucoside sold by Unigema. These block copolymers have the lowestHLB values and the highest molecular weights of the commerciallyavailable compounds contained within each of the four structuralsurfactant types. TABLE IV Cloud Point (° C.) Cloud Point (° C.) (8000ppm) (10% Solution) Ratio of AtPlus 542:31R1 100%  90% 43 63 80% 31 5170% 28 37 60% 27 28 50% 25 26 40% 23 24 30% 19 23 20% 16 21 10% 14 11 0% 12 5 Ratio of AtPlus 452:T150R1 100%  90% 30 45 80% 25 39 70% 21 2460% 19 22 50% 18 20 40% 17 19 30% 15 17 20% 16 15 10% 17 10  0% 9 2Ratio of AtPlus 452:L121 100%  90% 80 80 80% 75 80 70% 43 80 60% 23 8050% 17 75 40% 15 39 30% 13 24 20% 10 16 10% 8 9  0% 7 3 Ratio of AtPlus452:T1301 100%  90% 75 80 80% 56 80 70% 50 80 60% 38 80 50% 22 70 40% 2043 30% 18 29 20% 16 22 10% 14 15  0% 10 4

Thus, by using the polyglycosides/block copolymer blends of the instantinvention, one can not only select the most efficacious block copolymerfor maximizing the wetting effectiveness of a particular water repellentsoil, but also use it at high concentrations and, by adjusting thepolyglycoside: copolymer ratio produce a blend and concentrations with acloud point well above anticipated application temperatures, i.e.,produce a stable, water-soluble solution of the blends of thisinvention.

Alkyl polyglycosides are understood to be the reaction products ofsugars and fatty alcohols, suitable sugar components being the aldosesand ketoses such as glucose, fructose, mannose, galactose, talose,gulbse, allose, altrose, idose, arabinose, xylose, lyxose, lactose,sucrose, maltose, maltotriose, cellobiose, mellobiase, and ribose, whichare referred to hereinafter as glycoses. Particularly preferred alkylpolyglycosides are alkyl glucosides by virtue of the ready availabilityof glucose. In its broadest sense, the term “alkyl” in alkylpolyglycoside is intended to encompass the residue of an aliphaticalcohol, preferably a fatty alcohol, obtainable from natural fats, i.e.,saturated and unsaturated residues and also mixtures thereof, includingthose having different chain lengths. The terms alkyl oligoglycoside,alkyl polyglycoside, alkyl oligosaccharide and alkyl polysaccharideapply to alkylated glycoses of the type in which one alkyl radical inthe form of the acetal is attached to more than one glycose residue,i.e., to a polysaccharide or oligosaccharide residue; these terms aregenerally regarded as synonymous with one another. Accordingly, alkylmonoglycoside is the acetal of a monosaccharide. Since the reactionproducts of the sugars and the fatty alcohols are generally mixtures,the term alkyl polyglycoside is intended to encompass both alkylmonoglycosides and also alkyl poly(oligo)glycosides.

Optionally, there can be a polyoxyalkylene chain joining the alcoholmoiety and the saccharide moiety. The preferred alkoxide is ethyleneoxide.

The higher alkyl polyglycosides express surfactant properties. By“higher alkyl polyglycoside” is meant a glycoside having an alkylsubstituent that averages more than four carbon atoms in size.

The lipophilic groups in the alkyl polyglycosides are derived fromalcohols, preferably monohydric for compatibilizer applications andshould contain from 4 to 22, preferably 7 to 16 carbon atoms. While thepreferred groups are saturated aliphatic or alkyl, there may be presentsome unsaturated aliphatic hydrocarbon groups. Thus, the preferredgroups are derived from the fatty alcohols derived from thenaturally-occurring fats and oils, such as octyl, decyl, dodecyl,tetradecyl, hexadecyl, octadecyl, oleyl and linoleyl, but groups may bederived from synthetically produced Ziegler alcohols or oxo alcoholscontaining 9, 10, 11, 12, 13, 14 or 15 carbon atoms. The alcohols ofnaturally-occurring fatty acids, typically containing an even number ofcarbon atoms and mixtures of alcohols, are commercially available suchas mixtures of C₈ and C₁₀, C₁₂ and C₁₄, and the like.Synthetically-produced alcohols, for example those produced by an oxoprocess, contain both an odd and even number of carbon atoms such as theC₉, C₁₀, C₁₁ mixtures.

From their production, the alkyl polyglycosides may contain smallquantities, for example 1 to 2%, of unreacted long-chain alcohol whichdoes not adversely affect the properties of the surfactant systemsproduced with them.

Specifically, the preferred alkyl polyglycosides for use in the presentinvention are obtained by the reaction of alkanols with glucose or othermono- or di- or polysaccharides. Preferred alkyl polyglycosides for usein the present invention are the alkyl polyglucosides obtained by thereaction of glucose with a straight or branched chain alkanol or mixtureof alkanols, for example, a mixture of alkanols containing 4 to 22,preferably 7 to 16 carbon atoms, for example, 8 to 10 carbon atoms. Thenumber of glucose groups per alkyl group in the molecule may vary andalkyl mono- or di- or polyglucose or saccharide derivatives arepossible. Commercial alkylpolyglucosides usually contain a mixture ofderivatives having an average number of glycose groups per alkyl group(the Degree of Polymerization or D.P.) of between 1 and 4 for example,preferably from 1 to 2. A number of suitable alkylpolyglycosides arecommercially available and include, for example, AL2042 (ICI); AGRIMUL2069 and AGRIMUL PG 2067 (Cognis) and ATPLUS 438 and ATPLUS 452(Uniqema).

Illustrative of the many processes available for the preparation ofalkyl polyglycosides useful in the present invention are those disclosedin the following U.S. Pat. Nos. 4,950,743; 5,266,690; 5,304,639;5,374,716; 5,449,763; and 5,457,190.

It is anticipated that the compositions of the instant invention be alsoutilized in solid form, e.g., powder or granular form, by either beingadded to inert filler material and/or blended with fillers and additivesin methods well known by those skilled in the agrochemical waterdispersible or dry spreadable art. In this way, the compositions areable to be delivered in solid form to the water repellent soil andcontrolled release of the compositions can be achieved if one sodesires.

The metes and bounds of the instant discovery are as set forth in thefollowing paragraphs.

1. A process for increasing the wetting rate of water repellent soil which comprises the steps of: i) preparing an aqueous wetting agent composition consisting of a) an ethylene oxide-propylene oxide block copolymer (A) wherein the copolymer has an IT value of less than or equal to 2; an average molecular weight of greater than 3,000; and a percent hydrophile of less than or equal to 10; and b) water; and ii) intimately contacting water repellent soil with an amount of said wetting agent composition such that the EO/PO block copolymer (A) is present in the soil in an amount that, were it to be the only wetting rate increasing active present in the soil, it would provide a measurable increase in the wetting rate of the soil.
 2. The process of claim 1 wherein the total concentration of the block copolymer (A) in the wetting agent composition is from 200,000 ppm to 2 ppm.
 3. The process of claim 1 wherein the ethylene oxide-propylene oxide block copolymer (A) is selected from the group consisting of: i) straight block polymeric glycols obtained by the addition of ethylene oxide (EO) on a condensation product of propylene oxide (PO) with propylene glycol; ii) reverse block polymeric glycols obtained by the addition of propylene oxide (PO) on a condensation product of ethylene oxide (EO) with ethylene glycol; iii) tetra functional block copolymers obtained by the sequential addition of initially propylene oxide and then ethylene oxide to ethylene diamine; and iv) tetra functional reverse block copolymers obtained by the sequential addition of initially ethylene oxide and then propylene oxide to ethylene diamine.
 4. The process of claim 1 wherein the composition consists of a) an ethylene oxide—propylene oxide block copolymer (A) wherein the copolymer has an HLB value of less than or equal to 2; an average molecular weight of greater than 3,000; and a percent hydrophile of less than or equal to 10; b) an ethylene-propylene oxide block copolymer (B) having an HLB value greater than 2 and an average molecular weight of from 2,000 to 8,000; and c) water.
 5. The process of claim 4 wherein the composition consists of a) from 99 to 1 parts by weight copolymer (A); and b) from 1 to 99 parts by weight copolymer (B) wherein the parts by weight is based on the total weight of copolymers (A) and (B).
 6. A process for increasing the wetting rate of water repellent soil which comprises the steps of: i) preparing an aqueous wetting agent composition consisting of a) an ethylene oxide—propylene oxide block copolymer (A) wherein the copolymer has an HLB value of less than or equal to 2; an average molecular weight of greater than 3,000; and a percent hydrophile of less than or equal to 10; b) an alkylpolyglycoside; and c) water, and ii) intimately contacting water repellent soil with an amount of said wetting agent composition such that the EO/PO block copolymer (A) is present in the soil in an amount that, were it to be the only wetting rate increasing active present in the soil, it would provide a measurable increase in the wetting rate of the soil.
 7. The process of claim 6 wherein the composition consists of a) from 99 to 1 parts by weight copolymer (A); and b) from 1 to 99 parts by weight alkylpolyglycoside wherein the parts by weight is based on the total weight of copolymer (A) and the alkylpolyglycoside.
 8. A process for increasing the wetting rate of water repellent soil which comprises the steps of: i) preparing an aqueous wetting agent composition consisting of a) an ethylene oxide—propylene oxide block copolymer (A) wherein the copolymer has an HLB value of less than or equal to 2; an average molecular weight of greater than 3,000; and a percent hydrophile of less than or equal to 10; b) an ethylene-propylene oxide block copolymer (B) having an HLB value greater than 2 and an average molecular weight of from 2,000 to 8,000; c) an alkylpolyglycoside; and d) water; and ii) intimately contacting water repellent soil with an amount of said wetting agent composition such that the EO/PO block copolymer (A) is present in the soil in an amount that, were it to be the only wetting rate increasing active present in the soil, it would provide a measurable increase in the wetting rate of the soil.
 9. The process of claim 8 wherein the composition consists of a) from 98 to 1 parts by weight copolymer (A); b) from 1 to 98 parts by weight copolymer (B); and c) from 1 to 98 parts by weight alkylpolyglycoside wherein the total parts by weight is 100 and is based on the total weight of copolymer (A); copolymer (B); and the alkylpolyglycoside.
 10. A process for increasing the wetting rate of water repellent soil which comprises the steps of: i) preparing a solid granular or powder wetting agent composition consisting of an ethylene oxide-propylene oxide block copolymer (A) wherein the copolymer has an HLB value of less than or equal to 2; an average molecular weight of greater than 3,000; and a percent hydrophile of less than or equal to 10; and ii) intimately contacting water repellent soil with said solid wetting agent composition such that the EO/PO block copolymer (A) is present in the soil in an amount that, were an aqueous composition were to be prepared consisting only of water and said copolymer (A) and intimately applied to said soil such that the copolymer (A) concentration in said soil is the same as when the solid wetting agent composition is applied, said copolymer (A) amount would provide a measurable increase in the wetting rate of the soil.
 11. A process for increasing the wetting rate of water repellent soil which comprises the steps of: i) preparing a solid granular or powder wetting agent composition containing an ethylene oxide-propylene oxide block copolymer (A) wherein the copolymer has an HLB value of less than or equal to 2; an average molecular weight of greater than 3,000; and a percent hydrophile of less than or equal to 10; ii) adding said solid wetting agent composition to water to form an aqueous wetting agent composition; and iii) intimately contacting water repellent soil with an amount of said aqueous wetting agent composition such that the EO/PO block copolymer (A) is present in the soil in an amount that, were it to be the only wetting rate increasing active present in the soil, it would provide a measurable increase in the wetting rate of the soil. 